CN107065483B - Film and image heating apparatus using the same - Google Patents

Abstract

The invention provides a film and an image heating apparatus using the same. A cylindrical film used in an image heating apparatus that heats a recording material on which an image has been formed, the cylindrical film having a resin layer made of a resin in which a crystalline resin and an amorphous resin having a higher glass transition temperature than the crystalline resin are blended, wherein a volume ratio of the crystalline resin to the amorphous resin in the resin layer is 70/30 to 99/1.

Description

Film and image heating apparatus using the same

The present application is a divisional application of chinese patent application having application No. 201410436465.1, application date 2014, 08 and 29, and having the title "film and image heating apparatus using the film".

Technical Field

The present invention relates to a film used in an image heating apparatus such as a fixing apparatus.

Background

An image forming apparatus such as an electrophotographic copying machine, an electrophotographic printer, or the like is provided with, for example, an image forming unit that forms a toner image on a recording medium and a fixing device (image heating device) that performs a heating process to fix the toner image on the recording medium. The fixing device forms a nip portion between a fixing rotating member and a pressing rotating member that rotate in pressure contact with each other, thereby heating a recording medium on which an unfixed toner image has been formed by an image forming unit while nipping and conveying, thereby fixing the toner image on the recording medium.

In such a fixing device, conventionally, for example, a heat-resistant film fixing film is used as a fixing rotating member or a pressing rotating member. Japanese patent application laid-open No.3-25481 discloses the use of a thermoplastic resin such as Polyetheretherketone (PEEK), Polyethersulfone (PESU), Polyetherimide (PEI), or the like as a material of a fixing film. The thermoplastic resin can be produced by a production method such as extrusion molding, and therefore has the following advantages: can be produced at a lower cost than thermosetting resins.

However, if a thermoplastic resin is used as a material for the fixing film, there is a fear that fatigue cracking may occur due to insufficient bending resistance. On the other hand, if a thermoplastic film is used as a material of the fixing film, there is a possibility that abrasion of the inner peripheral surface of the film increases due to insufficient abrasion resistance, and slipping of the fixing film may occur due to resistance caused by abrasion dust.

Disclosure of Invention

A preferred embodiment of the invention of the present application is a cylindrical film used in an image heating apparatus that heats a recording medium on which an image has been formed, the cylindrical film including:

a resin layer made of a resin obtained by blending a crystalline resin and an amorphous resin having a higher glass transition temperature than the crystalline resin,

wherein the volume ratio of the crystalline resin to the amorphous resin in the resin layer is 70/30 to 99/1.

A second preferred embodiment of the invention of the present application is an image heating apparatus that performs a heating process of heating while conveying a recording material on which an image has been formed in a nip portion, including:

a cylindrical film having a resin layer made of a resin obtained by blending a crystalline resin and an amorphous resin having a higher glass transition temperature than the crystalline resin;

a nip forming member in contact with an inner surface of the film; and

a support member forming the nip portion together with the nip portion forming member via the film,

wherein the volume ratio of the crystalline resin to the amorphous resin in the resin layer is 70/30 to 99/1.

A third preferred embodiment of the invention of the present application is a cylindrical film used in an image heating apparatus that heats a recording material on which an image has been formed, comprising:

a resin layer in which a crystalline polyaryl ketone and an amorphous resin having a higher glass transition temperature than the crystalline polyaryl ketone are blended,

wherein the resin layer has two or more glass transition temperatures as measured by differential scanning calorimetry.

A fourth preferred embodiment of the invention of the present application is a cylindrical film used in an image heating apparatus that heats a recording material on which an image has been formed, comprising:

a resin layer made of a crystalline thermoplastic resin, the resin layer having a crystallinity of not less than 81% of the maximum saturated crystallinity of the crystalline thermoplastic resin.

Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).

Drawings

FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention;

FIGS. 2A to 2C are views showing the constitution of a fixing device according to an embodiment of the present invention;

fig. 3 is a schematic cross-sectional view of an image forming apparatus according to a first embodiment of the present invention;

FIG. 4 is a graph showing the change with time in temperature of a film according to the first embodiment of the present invention;

FIG. 5 is a conceptual diagram showing the abrasion susceptibility of a crystalline resin and an amorphous resin;

FIG. 6 is a graph showing the volume ratio and bending resistance of PEEK;

FIGS. 7A-7C are schematic diagrams showing the dispersed state of the base layer of the membrane;

FIG. 8 is a graph showing the volume ratio and the abrasion loss of PEEK;

FIG. 9 is a schematic view showing an estimated mechanism of wear suppression of the film relating to the first embodiment;

FIG. 10 is a schematic cross-sectional view showing another configuration of a fixing device according to an embodiment of the present invention;

FIG. 11 is a schematic cross-sectional view showing another configuration of a fixing device according to an embodiment of the present invention;

fig. 12 shows the results of an MIT test of a fixing film according to a sixth embodiment;

fig. 13 shows the results of DSC of the fixing film according to the sixth embodiment;

FIG. 14 is a schematic view of a fixing device relating to a sixth embodiment;

FIG. 15 shows the relationship between annealing time and crystallinity;

fig. 16 shows a longitudinal temperature distribution of the fixing belt during paper passage;

fig. 17 shows the outer diameter distribution of the fixing belt after the passage of the sheet in the sixth embodiment and the sixth comparative example.

Fig. 18 shows an outer diameter ratio of the fixing belt and an occurrence rate of paper wrinkles;

fig. 19 shows an outer diameter ratio and crystallinity of the fixing belt;

fig. 20 shows the temperature of the fixing belt and the elastic modulus of the fixing belt; and

fig. 21 is a cross-sectional view of a fixing device relating to a seventh embodiment.

Detailed Description

(first embodiment)

(1) Image forming apparatus with a toner supply device

Fig. 1 is a schematic cross-sectional view showing a schematic composition of an image forming apparatus (full-color printer) 100 according to an embodiment of the present invention. Among them, an image forming apparatus forms an image on a recording medium using a developer (toner) using an electrophotographic image forming process. For example, the image forming apparatus includes an electrophotographic copying machine, an electrophotographic printer (an LED printer, a laser beam printer, or the like), an electrophotographic facsimile apparatus, an electrophotographic word processor, or a multi-function printer of these apparatuses. Also, the recording medium is an article on which an image is formed, and is, for example, recording paper, an OHP sheet, a plastic sheet, cloth, or the like.

An image forming unit that forms toner images on the recording medium P is composed of four image forming stations Pa, Pb, Pc, Pd. The image forming stations each have a photoreceptor 117, a charging member 119, a lens scanner 118, a developer 120, a transfer member 124, and a cleaner 122 for cleaning the photoreceptor. Further, the image forming unit has a belt (intermediate transfer member) 123 that holds and conveys the toner image, and a secondary transfer roller 121 that transfers the toner image from the belt 123 onto the recording medium P. The operation of the image forming unit is well known, and thus a detailed description thereof is omitted here.

The recording medium P is output one sheet at a time from the cassette 102 by the rotation of the roller 105, and is conveyed to a secondary transfer nip formed by the belt 123 and the secondary transfer roller 121 due to the rotation of the roller 106. The belt 123 is tensioned between the tension roller 125a and the secondary transfer opposing roller 125b, and is rotated by the rotation of these rollers. The secondary transfer counter roller 125b is brought into contact with the secondary transfer roller 121 via the belt 123, thereby forming the above-described secondary transfer nip. The recording medium P to which the unfixed toner image has been transferred in the secondary transfer nip portion is conveyed to the fixing unit 109, whereby the toner image is heated and fixed. By the rotation of the roller 111, the recording medium P leaving the fixing unit 109 is discharged onto the tray 112.

(2) Fixing unit (fixing device) 109

A fixing device constituting the fixing unit 109 will now be described with reference to fig. 2A to 2C. Fig. 2A is a cross-sectional view showing a schematic configuration of the fixing device 109 according to the present embodiment. Fig. 2B is a front view of the fixing device 109 according to the present embodiment, viewed from the upstream side in the conveying direction of the recording medium. Fig. 2C is a diagram showing a schematic configuration of the ceramic heater 15 of the fixing device 109 according to the present embodiment.

The fixing device 109 has a heating unit 10 and a pressure roller 30 forming a pressure member. The heating unit 10 includes a cylindrical film (annular film) 16, a film guide 19 forming a supporting member, a ceramic heater (heat source) 15 forming a nip forming member, and the like. The film 16, the film guide 19, the ceramic heater (hereinafter referred to as "heater") 15, and the pressure roller 30 are members that are long in a direction perpendicular to the conveying direction of the recording medium (see fig. 2A).

The heater 15 forming a heat generating component is supported on the film guide 19, and the cylindrical film 16 having flexibility is loosely mounted on the outside of the film guide 19. The nip portion N is formed by the film 16 and the pressure roller 30 by sandwiching the film 16 between the heater 15 and the pressure roller 30.

The various components are described in more detail below. The pressing roller 30 has a circular shaft-shaped core metal core (shaft portion) 30A made of a metal material such as iron, stainless steel, aluminum, or the like. An elastic layer 30B having silicon rubber or the like as a main component is formed in a roll shape on the outer peripheral surface between the support shaft portions 30A1 at both ends of the metal core 30A in the longitudinal direction (see fig. 2B). Further, a releasing layer 30C having PTFE, PFA, FEP, or the like as a main component is formed on the outer peripheral surface of the elastic layer 30B. Support shaft portions 30A1 at both longitudinal end portions of the metal core 30A are rotatably supported via bearings 41 on left and right side plates 40 constituting a part of the metal frame 39 of the fixing device 109.

The film guide 19 is formed with a substantially concave cross section using a prescribed heat-resistant material. A groove 19A is formed in the flat surface of the film guide 19 on the pressing roller 30 side in the longitudinal direction. The grooves support the heater 15.

The heater 15 has a thin plate-like heater substrate 15A whose main component is ceramic, for example, alumina, aluminum nitride, or the like. On the film sliding surface on the film 16 side of the heater substrate 15A, an energization heat generating resistor 15B whose main component is silver, palladium, or the like is printed as a pattern in the longitudinal direction of the heater substrate. Further, on the film sliding surface, a conductive portion 15C for passing a current to the conductive heat-generating resistor 15B and an electrode portion 15D for supplying a current to the conductive heat-generating resistor via the conductive portion are printed as patterns. Further, a protective layer 15E whose main component is glass or fluororesin, or a heat-resistant resin such as polyimide is provided on the film sliding surface to cover the energization heat-generating resistor 15B.

The film 16 is formed in a cylindrical shape such that the inner circumference of the film is longer than the outer circumference of the film guide 19, and is loosely fitted onto the film guide in a tension-free state. The layer structure and material of the film 16 will be explained below.

The film 16 externally fitted to the film guide 19 is disposed in parallel with the pressure roller 30, and the film guide 19 is driven in a horizontal direction in which each end in the longitudinal direction perpendicularly intersects with the generatrix direction of the pressure roller via a pressure spring 42. The heater 15 supported by the film guide 19 in a pressed state brings the film 16 into contact with the outer peripheral surface (front surface) of the pressing roller 30 due to the pressing force of the pressing spring 42. Thereby, the elastic layer 30B of the pressure roller 30 is depressed and elastically deformed, and a nip portion N of a prescribed width is formed between the surface of the pressure roller 30 and the outer peripheral surface (front surface) of the film 16 (see fig. 2A).

In fig. 2A, reference numeral 43 is a guide device that guides the recording medium P to the nip portion N. Reference numeral 44 is a guide device that guides the recording medium P output from the nip portion N.

Referring to fig. 2A and 2C, a heat fixing process operation of the fixing device 109 will be described. A driving force of a motor (not shown) provided in the image forming apparatus is transmitted to a gear (not shown) provided in a longitudinal end portion of the metal core 30A of the pressure roller 30, thereby rotating the pressure roller 30 in the direction of the arrow. According to the rotation of the pressure roller 30, the film 16 rotates in the direction of the arrow while the inner peripheral surface (inner surface) of the film 16 slides against the protective layer 15E of the heater 15.

By the commercial power source 203, a current is passed through the heating resistor 15B of the heater 15 via the triac 202, whereby heat is generated by the energization heating resistor and the heater is warmed up. The triac element 202 is controlled by the control unit 200 composed of a CPU and a memory such as a RAM, a ROM, or the like, in such a manner that the detection temperature of the temperature detection element 201 monitoring the temperature of the film non-sliding surface of the heater substrate 15A is maintained at the fixing temperature (target temperature).

The recording medium P carrying the unfixed toner image T is guided to the nip portion N by the guide device 43. While the recording medium P is nipped and conveyed by the nip portion N, heat of the heater 15 and pressure of the nip portion are applied to the unfixed toner image T, thereby heating and fixing the unfixed toner image T onto the recording medium P. The recording medium P leaving the nip N is guided by the guide 44 and conveyed to the roller 111.

(3) Membrane 16

The film 16 is in a cylindrical shape having an outer diameter of 18mm, and a releasing layer 16B made of PFA 30 μm thick is provided on a base layer 16A 120 μm thick (fig. 3). Preferably, the average value of the total thickness of the base layer 16A is in the range of 50 to 400 μm, and more preferably, in the range of 70 to 200 μm. If the fixing film is too thin, it tends to become difficult to achieve a uniform thickness. On the other hand, if the fixing film is too thick, flexibility tends to decrease. The film 16 was rotated at a speed of 170 mm/sec at the outer peripheral surface while being pressed against the heater 15 with a pressure of 15kg by the pressure roller 30.

The main component of the base layer 16A is a thermoplastic resin. The thermoplastic resin does not require a heat curing step in the case of a thermosetting resin, and therefore, when the film 16 is manufactured, a conventionally known simple method, such as extrusion molding, injection molding, blow molding, inflation film molding, or the like, can be employed. In the present embodiment, extrusion molding is used as the method for producing the film 16.

Thermoplastic films can be broadly classified into two types based on crystallinity: crystalline resins such as PEEK, and amorphous resins such as sulfonated polyetherimide (sulfonated PEI), polyphenylsulfone (PPSU), and the like. In the present embodiment, the material for the base layer 16A is a blend resin combining 70% by volume of a crystalline resin and 30% by volume of an amorphous resin. PEEK (381G, manufactured by Victrex, Tg ═ 143 ℃) was used as a crystalline resin, and sulfonated PEI (Ultem XH6050, manufactured by SABIC, Tg ═ 247 ℃) was used as an amorphous resin.

If charging during image formation is feared and if improvement in mechanical strength is required, a filler may be added to the base layer 16A. Examples of fillers added are, for example, carbon black, graphite powder, carbon nanotubes, metal powder, metal oxide whiskers, and the like. Among these, carbon black is particularly preferable from the viewpoint of mechanical properties. Examples of carbon blacks may include: ketjen black, acetylene black, oil furnace black, pyrolytic carbon black, and channel black. One kind of these kinds of carbon blacks alone or two or more kinds of these kinds of carbon blacks in combination can be used. The particle size of the filler is not less than 3nm and less than 1000nm, more preferably, not less than 5nm and less than 300 nm. If the particle size of the filler is too small, handling during addition to the resin may become more difficult. If the particle size of the filler is too large, film formation may be difficult. Also, the proportion of the filler in the resin composition of the film is not less than 1 part by mass and not more than 40 parts by mass, more preferably not less than 3 parts by mass and not more than 20 parts by mass with respect to 100 parts by mass of the thermoplastic resin. If the proportion of the filler is too large, mechanical properties may be reduced due to increased brittleness of the fixing film. If the proportion of the filler is too small, the volume resistivity of the fixing film may become too high. Further, the film 16 used is a film in which residual stress generated during molding is removed by annealing treatment and crystallization treatment is performed in order to obtain desired initial strength and heat resistance.

Next, the temperature state of the film 16 during the heat fixing process operation of the fixing device 109 will be described. Although it depends on the thickness and size of the recording medium P used, the fixing film 16 is heated to a range of about 80 ℃ to about 240 ℃ during image formation.

FIG. 4 shows the use of a glass having a thickness of 80g/cm²The temperature of the film 16 when the quantitative a 4-sized paper (Red Label 80, manufactured by Canon) was used as the recording medium P. Until the recording medium P reaches the nip portion N, the temperature of the film 16 is raised to 165 ℃ by the heater 15. When the recording medium P passes through the nip portion N, the temperature of the film 16 becomes 165 ℃.

(4) Fatigue cracking and slipping of fixing film

The conventional film 16 uses only a crystalline resin or only an amorphous resin as a material of the base layer. If only crystalline resin is used as the material of the base layer of the film 16, abrasion (wear) is liable to occur, and if only amorphous resin is used as the material of the base layer of the film 16, fatigue cracking is liable to occur.

First, fatigue cracking in the conventional film 16 is explained in detail. Since a force is applied from the pressure roller 30 in the nip portion N, the curvature of the film 16 varies with the position in the circumferential direction. Therefore, the film 16 is repeatedly bent when the film 16 is rotated. For example, if only an amorphous resin is used as the material of the film 16, cracks (so-called fatigue cracks) may occur due to the repeated bending. The reason for this is that amorphous resins generally do not withstand repeated bending stresses.

Next, the abrasion of the conventional film 16 is explained in detail. The film slides relative to the heater 15 at a temperature (process temperature) of 165 ℃. For example, if the material of the film 16 is a single thermoplastic resin, the abrasion of the film is drastically deteriorated when the film 16 exceeds the glass transition temperature Tg of the thermoplastic resin (fig. 5). This is because the temperature higher than the glass transition temperature Tg activates the movement of molecules in the amorphous portion, and the resin suddenly becomes soft. If there is such a large film abrasion, the frictional resistance between the film 16 and the heater 15 becomes larger due to the viscosity of the abrasion powder, and a slip preventing the film 16 from rotating following the roller may occur. If slipping occurs, unevenness occurs in heat transfer to the recording medium P, and unevenness occurs in gloss of the image. Crystalline resins have a stronger fatigue crack resistance than amorphous resins, but generally have a lower glass transition temperature, Tg, than amorphous resins. In other words, with the conventional film 16, it is difficult to simultaneously solve the wear and the fatigue crack.

(5) Suppression of fatigue cracking and slip in membrane 16

First, the fatigue crack suppression effect of the present embodiment will be described. The relationship between the blending ratio of a 120 μm thick film formed by extrusion molding of a blended resin of PEEK and sulfonated PEI and the flexural strength thereof at 165 ℃ is shown in fig. 6. In addition to the fact that the film was tested while being heated to 165 ℃ with a hot air stream, the flexural strength was measured in accordance with JIS-P8115 (2001). As can be seen from the measurement results, the flexural strength greatly changes when the volume ratio of PEEK is in the range of 30% to 70%, and does not change significantly outside this range. In other words, when the volume ratio of PEEK is not less than 70%, the bending strength can be increased to substantially the same level as when the volume ratio of PEEK is 100%.

Further, when a 120 μm thick film formed by extrusion molding of a blend resin of PEEK and sulfonated PEI was observed by TEM, it could be seen that the dispersion state of the PEEK phase 60a and the sulfonated PEI phase 60b was varied with the volume ratio of PEEK, as shown in FIGS. 7A to 7C. Fig. 7A is a schematic view of the phase composition when the volume ratio of PEEK is 30% or less, fig. 7B is a schematic view of the phase composition when the volume ratio of PEEK is more than 30% and less than 70%, and fig. 7C is a schematic view of the phase composition when the volume ratio of PEEK is 70% or more.

Among them, the inventors speculate that the reason why the flexural strength can be improved by setting the volume ratio of PEEK to not less than 70% and adopting the phase composition shown in fig. 7C is as follows. Sulfonated PEI as an amorphous resin does not withstand repeated bending stresses, and thus sulfonated PEI phase 60b is liable to form starting points of cracks. If the sulfonated PEI phase 60b is arranged or isolated in islands, even if cracks occur in the sulfonated PEI, the development of cracks is limited by the PEEK phase 60a, and thus this does not directly cause fatigue cracking. On the other hand, if the sulfonated PEI phase 60b is connected in a continuous manner, cracks will develop only gradually in the sulfonated PEI phase 60b, without passing through the PEEK phase 60a, and thus fatigue cracks become worse.

Next, the abrasion suppressing effect of the film 16 according to the present embodiment will be described. The relationship between the blending ratio of a 120 μm thick film formed by extrusion molding of a blended resin of PEEK and sulfonated PEI and the abrasion amount thereof at 165 ℃ is shown in fig. 8. The abrasion amount is considered as the amount of change in weight of the film 16 when the roller 105 is rotated for 120 hours while the heater 15 is heated to achieve a temperature of 165 ℃ of the film 16 in the composition in which the blending ratio of the film 16 of the fixing unit 109 of the present embodiment is changed. As can be seen from the measurement results, the amount of abrasion greatly changes when the volume ratio of PEEK is in the range of 100% to 90%, and does not change significantly outside this range. In particular, the amount of wear greatly varies when the volume ratio of PEEK is in the range of 100% to 99%. In other words, even if a small amount of sulfonated PEI is blended with PEEK, the abrasion resistance can be improved. The present inventors speculate that the reason is as follows.

The blend materials of the polymer blend according to this embodiment are selected as: PEEK, which has a lower glass transition temperature Tg (143 ℃) than the temperature of 165 ℃ used in the heat treatment of the membrane 16, and sulfonated PEI, which has a glass transition temperature Tg (247 ℃) higher than said temperature. Thus, at a service temperature of 165 ℃ for the membrane 16, the PEEK phase 60a is soft and the sulfonated PEI phase 60b is hard. Thus, the PEEK phase 60a of the membrane 16 preferentially wears away during use, and as shown in fig. 9, the sulfonated PEI phase 60b exhibits a surface state protruding beyond the surface of the PEEK phase 60 a. Thus, the hard sulfonated PEI phase 60b is subjected to a large portion of the force from heater 15. Then, the soft PEEK phase 60a is less likely to receive a force from the heater 15, and thus abrasion of the PEEK phase 60a becomes less likely to progress.

From the above, in the present embodiment, the blending volume ratio (a/B) of the crystalline resin (a) to the amorphous resin (B) in the blended resin used in the base layer 16A of the film 16 is from 70/30 to 99/1. The effects of suppressing fatigue cracking and suppressing slipping of the present embodiment were confirmed in actual practice. More specifically, the composition of the present embodiment was evaluated for fatigue cracking after 50,000 sheets and slippage after 50,000 sheets. The paper passed through was Red Label 80. As a first comparative example, a composition was prepared in which the volume ratio (%) of the thermoplastic resin in the material of the base layer 16A of the first embodiment was changed to PEEK/sulfonated PEI (100/0, 50/50, 0/100). Table 1 shows the evaluation results. As shown in table 1, it can be seen that the first embodiment can suppress fatigue cracking and slipping.

[ Table 1]

[ second embodiment ]

A film to which a second embodiment of the present invention relates will now be described. Among them, only points different from the first embodiment are mainly explained, and the same constituent symbols as those of the first embodiment are assigned the same reference numerals and are not otherwise described herein. The matters not described here are the same as those in the first embodiment.

In the present embodiment, the same composition as in the first embodiment is adopted entirely except for the fact that Polyetherketoneetherketoneketone (PEKEKK) is used as the crystalline resin and PPSU is used as the amorphous resin. More specifically, in the present embodiment, the material for the base layer 16A is a blend resin that combines 70% by volume of a crystalline resin and 30% by volume of an amorphous resin. PEKEKK (HT, manufactured by Victrex, Tg ═ 162 ℃) was used for the crystalline resin, and PPSU (Radel R-5000, manufactured by Solvay Advanced Polymers (nowadays Solvay Specialty Polymers), Tg ═ 220 ℃) was used for the amorphous resin.

The effects of suppressing fatigue cracking and suppressing slipping of the present embodiment were confirmed in actual practice. The method of evaluation is the same as that employed in the first embodiment. As a second comparative example, a composition was prepared in which the volume ratio (%) of the thermoplastic resin in the material of the base layer 16A was changed to PEKEKK/PPSU 100/0, 50/50, 0/100. Table 2 shows the evaluation results.

[ Table 2]

It can be seen that in the second embodiment, fatigue cracking and slipping can be suppressed. In other words, even with the blend resin containing PEKEKK and PPSU, fatigue cracking and slipping can be suppressed by making the volume ratio of the crystalline resin not less than 70%.

As described in the present embodiment, the combination of the crystalline resin and the amorphous resin in the material of the base layer 16A is not limited to PEKEKK and PPSU, provided that the Tg of the amorphous resin is higher than that of the crystalline resin.

Further, since the base layer 16A may be deteriorated upon adhesion of toner components and the like, a crystalline polyaryletherketone resin having excellent chemical resistance is suitable as the crystalline resin. Crystalline polyaryletherketone resins are crystalline resins, including homopolymers, copolymers, terpolymers, graft copolymers, and the like, that contain monomer units that include more than one aryl group, more than one ether group, and more than one ketone group. For example, the resin can be selected from: PEEK, PEKEKK, Polyetherketone (PEK), Polyetherketoneketone (PEKK), polyaryletherketoneketone ketone (PAEKEKEKK), Polyaryletherketone (PAEK), Polyaryletherketone (PAEEK), Polyetheretherketoneketone (PEEKK), Polyaryletherketone (PAEKK), Polyaryletherketoneketone (PAEEKK), and the like. If the melting point is low, the resin melting temperature at the time of manufacturing the base layer 16a can be lowered, and it is particularly preferable to use PEEK as the crystalline resin because this facilitates manufacturing. Further, when a crystalline polyaryletherketone resin is used, the amorphous resin is preferably a resin having a glass transition temperature Tg sufficiently higher than that of the crystalline polyaryletherketone resin. Examples of such resins are e.g. sulfonated PEI, PPSU, PESU, Polysulfone (PSU) etc. Of these, sulfonated PEI has a particularly high glass transition temperature Tg, and thus, if used as a material for the base layer 16A, has advantages in the following respects: so that the restriction of the through-put (through-put) of the recording medium P having a narrow width is reduced. The reason for this will be explained below.

When the recording medium P having a narrow width is passed, the temperature of the portion of the film 16 in the longitudinal direction where the paper does not pass becomes higher than the temperature of the portion where the paper passes. In this case, in order to make the temperature of the portion of the film 16 where the paper does not pass not exceed the glass transition temperature Tg of the amorphous resin, the passage of the recording medium P must be slowed. This is because, if the temperature of the portion of the film 16 through which the paper does not pass exceeds the glass transition temperature Tg of the amorphous resin, the rigidity of the film 16 is suddenly lowered, which may cause breakage of the film. Therefore, by using sulfonated PEI having a high glass transition temperature Tg for the amorphous resin, the restriction of the passage of the recording medium P can be reduced.

Further, it is also possible to use a plurality of crystalline resins and to use a plurality of amorphous resins as the material of the base layer 16A. Also, for example, a combination of any one or more of PEEK, PEK, and PEKEKK can also be used as the crystalline resin and any one or more of sulfonated PEI, PPSU, and PESU as the amorphous resin.

Also, the film 16 according to the first and second embodiments is used for a composition having a heating source at the inner side of the film 16, but the present embodiment is not limited to this composition. Any composition may be employed provided that the film 16 undergoes repeated bending above the Tg temperature of the crystalline resin and the film 16 slides on the nip forming member 15 above the Tg temperature of the crystalline resin. For example, as shown in fig. 10, a composition in which a heating source 61 (halogen heater) is introduced into the inside of the metal core 60A can be adopted. Also, for example, a composition including a heating source 62 that heats the outer peripheral surface of the pressure roller 30 can also be employed, as shown in fig. 11. Also, a fixing device that introduces a halogen heater inside the film 16 may be employed.

In each of the embodiments described above, an example is given in which the present invention is applied to a heat fixing device that fixes an image to a recording medium by applying heat, but the application range of the present invention is not limited thereto. For example, the present invention can be widely applied to apparatuses that provide heat treatment to a heated applied medium, such as an image heating apparatus for modifying the surface of a recording medium to produce gloss on the surface of the recording medium by heating, an image heating apparatus for temporary fixing, a heat drying apparatus for a medium receiving the application of heat, a heat laminating apparatus, and the like.

In the present embodiment, the method of confirming the volume ratio of the blended resin is not particularly limited. For example, a conventionally known method can be employed in which an ultrathin section is produced by cutting the base layer 16A in a prescribed direction, stained with ruthenium tetroxide (RuO4) or the like, and observed with a Transmission Electron Microscope (TEM) or the like. In the case of this method, for example, the surface area ratio of each resin phase in the material of the base layer 16A in the cross section of the base layer 16A is a volume ratio.

[ third embodiment ]

The image forming apparatus and the fixing apparatus according to the present embodiment are the same as those of the first embodiment except for the film 16, and therefore, the description thereof is omitted here. Moreover, since the basic composition of the film 16 is the same as that of the first embodiment, the description thereof is omitted here. The differences from the membrane of the first embodiment will be described in detail herein. As described in the first embodiment, the fixing film 16 is heated to a range of about 80 ℃ to about 240 ℃ during the fixing process. Also, as described above, the fixing film 16 contacts in a state of being pressed by the outer circumferential surface of the pressing roller 30, and thus rotates in a state of being distorted within a range of elastic deformation. For the reasons given above, it is important that the fixing film 16 should maintain heat resistance in a wide range and maintain bending resistance in an elastic deformation range during the product life.

An object of the present embodiment is to provide a fixing film having high bending resistance, which is a cylindrical fixing film produced by extrusion molding using a blended resin of PEEK and PEI showing good compatibility.

(4) Differences between comparative examples and embodiments

In the method of manufacturing the fixing film, the fixing films according to embodiment 3-1, embodiment 3-2, and comparative example 3-5 were manufactured by the same method except for the fact that the composition of the blend resin used in the base layer 16A was changed to the composition shown in table 3.

Table 3 shows the results of confirming the performance of comparative example 3-5 and embodiments 3-1 and 3-2.

[ Table 3]

Comparative example 3 is a fixing film made of only PEEK. The fixing film has low heat resistance and has a possibility of breakage or deformation during image formation. This is because the glass transition temperature (Tg) of PEEK (Victrex381G) is 143 ℃, which is below the use temperature range. The glass transition temperature of sulfonated PEI (Sabic Ultem XH 6050) shown in comparative example 4 is a high value of 247 ℃, but since the resin is an amorphous resin and has poor bending resistance, there is a possibility of breakage or the like of the fixing film.

Comparative example 5 is a blended resin of PEEK (Victrex381G) and PEI (Ultem #1000) with good compatibility. The fixing film made of the blend resin disclosed in comparative example 5 did not have any problem in heat resistance and bending resistance when new, but when durability was confirmed using an image forming apparatus, a decrease in bending resistance after the durability test was observed.

On the other hand, in embodiment 3-1, there is no deterioration in heat resistance or bending resistance over the entire life of the image forming apparatus, and no problematic defect is observed. In embodiment 3-2, 10 parts of the conductive filler was added to 100 parts by mass of the blended resin in embodiment 3-1, and by setting an appropriate amount of the filler, the bending resistance after the initial period and the durability test did not have any problem, and good performance could be obtained.

The difference between comparative example 3 and embodiments 3-1 and 3-2 can be considered to be due to fatigue of the film in bending resistance. This will now be described by using the results of the MIT test (bending resistance test method) according to JIS P8115.

Regarding the test conditions, the radius of curvature of the curved surface of the bending jig was 0.38mm, the width of the test piece was 10. + -. 0.1, the load was 9.8N, and the bending angle was 135. + -.2 °. The number of bending operations until the test piece broke was taken as the number of bending endurance.

FIG. 12 shows the results of the MIT test for the new products of comparative example 5, embodiment 3-1, and embodiment 3-2, and the results of the MIT test after the durability test using the image forming apparatus. In the case of the combination of the materials in comparative example 3, the number of MIT after the durability test was significantly reduced. On the other hand, it can be seen that the fixing films having the materials in embodiments 3-1 and 3-2 show a small decrease in MIT before and after the durability test, and thus the bending resistance is stable throughout the product life.

The present inventors considered that the difference in durability between comparative example 5 and embodiments 3-1 and 3-2 was due to the miscible (mixing) state of the blended resin. The mechanism of the estimation will be described below.

When a fixing film is formed with a material made of a blended resin, it is considered that a miscible state between the resins forming the blended resin is important. If the resins are immiscible with each other, film forming properties are lowered and it is difficult to form a film shape when attempting to form a thin film, and there may be cases where: it can be formed into a film shape, but the film does not have mechanical strength required for practical use. On the other hand, in the case of the blended resins which are completely miscible as in comparative example 5, these resins are miscible together at the molecular level, and a film can be formed without any problem.

However, when the blend resin which is completely miscible is used as a fixing film in an image forming apparatus, it is presumed that the bending resistance is deteriorated in the growth process of the crystal. Crystallization is promoted if PEEK is exposed to high temperature, but the crystallization of PEEK in a blend resin that is completely miscible at a molecular level is considered to proceed in a state where PEI having good compatibility is encapsulated in the core of PEEK. In other words, it is considered that PEI, which has inferior bending resistance to PEEK, is introduced into the growth of crystal nuclei in the nuclei of PEEK, and thus the bending resistance is decreased in the comparative example. On the other hand, in the present embodiment, PEEK and sulfonated PEI form a gentle miscible state. Since the grain boundaries forming the immiscible portion are present in sufficiently small units as compared with the thickness of the film, the film forming performance is good and a film having sufficient mechanical strength is obtained. The present inventors considered that, due to the fact that crystallization of PEEK occurred without introducing sulfonated PEI into the nuclei of PEEK, there was no reduction in bending resistance when the blend resin having such a gradual miscible state was used as a fixing film in an image forming apparatus.

(5) Results of Differential Scanning Calorimetry (DSC) in comparative example 5 and embodiment 3

As shown below, Differential Scanning Calorimetry (DSC) was used herein to explain the difference between comparative example 5 and embodiment 3. First, a method for measuring the glass transition temperature (Tg) in the present embodiment will be described.

5-20mg, preferably 10mg, of the test sample are accurately weighed. The sample was introduced into an aluminum pan and measured at a temperature rise rate of 10 ℃/min within a measurement temperature range of 80 ℃ to 380 ℃ using an empty aluminum pan as a reference. The apparatus used for the assay was a Mettler Toledo DSC 823.

100 parts of PEEK

B70 parts by mass of PEEK/30 parts by mass of PEI (comparative example 5)

70 parts by mass of PEEK/30 parts by mass of sulfonated PEI (embodiment 3-1)

As shown in fig. 13B, in comparative example 5, although the resins were two types: the fact that a blend of PEEK (Tg 143 ℃) and PEI (Tg 217 ℃) was used, but a glass transition temperature (B) was observed at 159 ℃_PEEK). In other words, the glass transition temperature of PEEK in comparative example 5 shows a glass transition temperature (A) higher than that of 100 parts by mass of PEEK (pure PEEK)_PEEKHigh results at 143 ℃).

It is generally known that the glass transition temperature of the case where resins having different glass transition temperatures Tg1 and Tg2 are blended and completely miscible together is given by the FOX formula shown in formula (1). In comparative example 5, the observed glass transition temperature (159 ℃ C.) substantially coincided with the glass transition temperature (159.4 ℃ C.) obtained by the formula FOX, and therefore the blended resin in comparative example 5 was considered to have PEEK and PEI in a completely miscible state.

[ formula 1]

(W₁And W₂Is the weight ratio of each resin) formula (1)

On the other hand, in the case of embodiment 3-1 shown in FIG. 13C, there is a structure composed of PEEK (C)_PEEK) And sulfonated PEI (C)_S ^- _PEI) Two observed glass transition temperatures were induced. Glass transition temperature (C) derived from PEEK observed in embodiment 3-1_PEEK) Glass transition temperature (A) of 100 parts by mass of PEEK (pure PEEK) at 145 DEG C_PEEK) Are substantially the same. On the other hand, it was confirmed that the glass transition temperature (C) was caused by sulfonated PEI_S ^- _PEI) In the vicinity of 230 ℃, it migrates from the glass transition temperature of pure sulfonated PEI, i.e., 247 ℃ to the low temperature side. The inventors believe this is because sulfonated PEI and PEEK form a progressively miscible state, rather than a completely immiscible state.

It is considered that by setting 2 or more glass transition temperatures for the blended resin as described above, a progressive miscible state is formed. Therefore, the blend resin used in the present embodiment has 2 or more glass transition temperatures measured in differential scanning calorimetry. Further, it is preferable that the glass transition temperature of the blended resin as measured by differential scanning calorimetry due to the amorphous resin is lower than the glass transition temperature of the amorphous resin as measured by differential scanning calorimetry.

Further, from the results of the tensile modulus measurement in the film state, it can be seen that the material of the present embodiment forms a gradually miscible state, not a completely immiscible state. Table 1 shows the results of measuring the tensile modulus using a film having a thickness of 100 μm in an environment of 160 ℃.

In the present invention, the tensile modulus of a film 100 μm thick in an environment of 160 ℃ was measured by the method according to JIS 7127.

In comparative example 1, which is pure PEEK, a decrease in elastic modulus was observed above the glass transition temperature, and the tensile modulus in an environment of 160 ℃ was 0.76 GPa. The sulfonated PEI in comparative example 4 was below the glass transition temperature in an environment of 160 ℃ and had a high elastic modulus of 1.41 GPa. Comparative example 5, which is a blended resin with high compatibility, has an elastic modulus of 1.08GPa, and the elastic modulus is improved due to the addition of PEI. It is considered that this is because the reinforcing effect due to the addition of PEI was obtained in a film state due to high compatibility between resins and excellent film forming properties in comparative example 3. On the other hand, in embodiment 3-1, the tensile modulus was 1.04GPa, and the elastic modulus was improved by adding sulfonated PEI. Further, in embodiment 3-2, a further improvement in the elastic modulus was observed due to the addition of the filler. Also for this reason, embodiments 3-1 and 3-2 have excellent film-forming properties and are considered to show a gradual miscible state. This same tendency is observed in the film thickness range of 50-150 μm. As described above, in the present invention, the tensile modulus of a film-like sample 100 μm thick in the case of the blended resin is preferably higher than that in the case of the crystalline polyarylketone resin under the environment of a temperature of 160 ℃.

The present inventors made the following comments on the mechanism by which the blend resin of sulfonated PEI and PEEK shown in embodiment 3-1 forms a smooth miscible state without complete miscibility.

The structure of sulfonated PEI includes a sulfonyl group having a large polarity in the main chain of PEI, as shown in the following structural formula (1). PEEK and PEI intrinsically have very high compatibility, but due to the presence of highly polarized sulfur-containing sulfonyl groups, electrostatic forces due to polarization affect the interaction between molecules, and compatibility with PEEK becomes partially incompatible. Thus, it is preferable that the amorphous resin used in the blend resin relating to the present invention is a resin having a group having large polarity such as a sulfonyl group in the main chain.

The amorphous resin used in the present embodiment is a resin formed of any one or at least two of sulfonated Polyetherimide (PEI), Polyethersulfone (PES), polyphenylsulfone (PPSU), and polysulfone (PSf).

[ chemical formula 1]

As described above, by realizing a progressive miscible state between the crystalline polyarylketone resin and the amorphous resin, good film formation performance is ensured, and a fixed film can be provided in which there is no deterioration in bending resistance caused by the development of crystals as a result of use under high-temperature conditions.

[ fourth embodiment ]

The method of manufacturing a fixing film according to the present embodiment differs from the third embodiment only in the material of the fixing film used, and is the same as the third embodiment in all other respects, and therefore only the difference will be described here.

(6) Differences between comparative examples and embodiments

In the present embodiment, the fixing film 16 also forms a two-layer structure. In embodiment 4-1 (see Table 4), base layer 16A is a blended resin (90 μm thick) of PEEK (Victrex381G, Tg 143 ℃) as a crystalline polyaryl ketone resin and PPSU (Solvay Specialty Polymers Radel R-5000, Tg220 ℃) as an amorphous resin, and surface layer 16B is made of PFA pipe (DuPont 450HP) (30 μm thick).

In embodiment 4-2, the base layer 16A is a blended resin (90 μm thick) of PEEK (Victrex381G, Tg 143 ℃ C.) as a crystalline polyaryl ketone resin and PES (Solvay Specialty Polymers heel polyester sulfofone, Tg220 ℃ C.) as an amorphous resin, and the surface layer 16B is made of a PFA tube (DuPont 450HP) (30 μm thick).

In embodiments 4-1 and 4-2, the average of the total thickness of the fixing film 16 was 120 μm.

The results of comparing the performances of the fixing film 16 of the present embodiment and the film 16 of comparative example 5 using the above-described image forming apparatus are shown in table 4. Embodiment 4-1 shows little deterioration in heat resistance or bending resistance over the life of the image forming apparatus. In embodiment 4-1, too, although PPSU is used as an amorphous resin, deterioration during the durability test is small. Further, the tensile modulus in the state of a film of 100 μm thickness was also similar to that of comparative example 5 in which the resin was completely miscible (see Table 4).

Further, the Tg of the blended resin in the fixed film in embodiment 4-1 was 150 ℃ and 210 ℃ (due to the amorphous resin), and the Tg of the blended resin in the fixed film in embodiment 4-2 was 152 ℃ and 208 ℃ (due to the amorphous resin).

[ Table 4]

Due to the above, although the resins are not completely miscible in embodiments 4-1 and 4-2, since the resins are dispersed in very small units, sufficient mechanical strength can be obtained. Further, it is considered that by making PEEK not completely miscible with the amorphous resin, crystal nuclei of PEEK grow separately from the amorphous resin upon crystallization of PEEK, and thus deterioration due to the durability test is slight.

The structural formulae of PPSU and PES are shown below. In both cases, the structure includes a sulfonyl group in the backbone. As previously mentioned, sulfonyl groups include sulfur and have a large polarity. It is presumed that the compatibility with PEEK becomes partially incompatible due to the influence of electrostatic force caused by polarization of sulfonyl group on molecular interaction with PEEK.

[ chemical formula 2]

Structural formula of PPSU

PES structural formula

As described above, by setting the blend resin of the crystalline polyaryl ketone resin and PPSU and the blend resin of the crystalline polyaryl ketone resin and PES to a gradually miscible state, good film formation performance is ensured, and a fixing film can be provided which shows little deterioration in bending resistance due to the progress of crystallization when used at high temperatures.

[ fifth embodiment ]

In the present embodiment, the fixing device used is different. The composition is explained below with reference to fig. 14. The fixing device includes a fixing roller 410 having a heating source 420, for example, a halogen lamp, therein, a fixing film 16 that rolls on the fixing roller 410 and conveys paper, and a fixing pad 460 that is disposed in contact with the inner peripheral side of the cylindrical fixing film 16 and forms a fixing nip portion N between the fixing roller 410 and the fixing film 16. The fixing pad 460 in the present embodiment is composed of a pressing pad 460a as a low pressure pad portion disposed on the upstream side and a fixing pad 460b as a high pressure pad disposed on the downstream side with a pressing force higher than that of the pressing pad 460a, which are arranged in a separated state in the following manner: the width of the fixing nip portion is the same from the center of the fixing pad 460 to both ends thereof. The pressing pad 460a and the fixing pad 460b are supported by a rigid support 470 having a recess for supporting the pads (460a and 460b), and the fixing film 16 is pressed against the surface of the fixing roller 410 from the back surface side of the fixing film 16. Further, in order for the fixing film 16 to rotate smoothly, a belt running guide 45 made of, for example, a rigid resin having low thermal conductivity is provided at a lower portion of the rigid support 470.

A temperature sensor 490 for measuring the surface temperature of the fixing roller 410 is provided around the fixing roller 410, and the temperature of the heating source 420 is controlled by the temperature sensor 49 so that the surface temperature of the fixing roller 410 becomes a predetermined temperature. The temperature sensor 490 is not particularly limited as long as the sensor can measure the surface temperature of the fixing roller 410, and a sensor element such as a thermistor, a positive temperature coefficient thermistor (Posistor), or the like can be used.

The fixing roller 410 according to the present embodiment is constituted by: a cylindrical core 410a made of metal such as aluminum, having excellent mechanical strength and good thermal conductivity; an elastic layer 410b such as silicon rubber, which is formed on the surface of the core 410 a; and a releasing layer 410c placed on the surface of the elastic layer 410b and provided in order to prevent the unfixed toner image from being biased on the paper.

Among them, the material of the core 410a is not particularly limited, provided that the material has mechanical strength and good thermal conductivity, and a metal or an alloy such as stainless steel, or brass may be used. Also, the elastic layer 410b is not limited to silicone rubber, and as long as the layer has heat resistance, for example, fluororubber can be used. The method of forming the elastic layer 410b on the surface of the core 410a is also not particularly limited, and an injection molding method, a coating method, or the like may be employed. The release layer 410c is required to have heat resistance and appropriate releasability from the toner, and for example, fluororubber, fluororesin, or the like is used. Further, the heating source 420 inside the fixing roller 410 is not particularly limited, provided that the heating source has a shape and a structure capable of being housed inside the core 410a, and can be appropriately selected according to the purpose without any problem.

(7) Description of the fixing film 16 relating to the present embodiment

The fixing film according to the fifth embodiment was produced in the same manner as in embodiment 3-1, using a blended resin (120 μm thick) of PEEK (Victrex381G, Tg 143 ℃) as a crystalline polyaryl ketone resin and PSf (Solvay Advanced Polymers UDEL P-1700, Tg 189 ℃) as an amorphous resin, and a PFA pipe (DuPont 450HP) (30 μm thick) as the surface layer 16B. In the fifth embodiment, the blending ratio in the base layer 16A is 70 parts by mass of PEEK and 30 parts by mass of PSf with respect to 100 parts by mass of the resin. The total thickness of the fixing film 16 has an average value of 100 μm. The Tg values of the blend resin in the fixing film according to the fifth embodiment are 148 ℃ and 180 ℃ (due to the amorphous resin). Further, the tensile modulus (100 μm thick film) in an environment of 160 ℃ was GPa.

In the fixing device according to the present embodiment, a fixing roller 41 having a three-layer structure and a recording medium are present between the fixing film 16 and the heating source 42. Therefore, the fixing film 16 is less likely to reach a high temperature by the heat from the heating source 42 due to the influence of the thermal resistance of the components.

Even in the above-described embodiment, the blended resin can be formed into a progressively miscible state, heat resistance and bending resistance are not problematic, and a fixing film showing little deterioration over the life of the image forming apparatus can be provided.

The structural formula of PSf is shown below. PSf also has a structure including a sulfonyl group in the main chain. As previously mentioned, sulfonyl groups include sulfur and have a large polarity. It is presumed that the compatibility with PEEK becomes partially incompatible due to the influence of electrostatic force caused by polarization of sulfonyl group on molecular interaction with PEEK.

[ chemical formula 3]

As described above, by achieving a state of progressive miscibility in the crystalline polyarylketone resin and the PSf blend resin, good film formation properties are ensured, and a fixed film can be provided in which there is little deterioration in bending resistance due to the progress of crystallization as a result of use at high temperatures.

[ sixth embodiment ]

The image forming apparatus and the fixing apparatus according to the present embodiment are the same as those of the first embodiment, and therefore, the description thereof is omitted here. The thermoplastic endless fixing belt (film) may have an increased crystallinity and a contracted outer diameter. After successive passes of small size paper, such as a5 paper, there may be substantially no variation in the outer diameter in the portion where the paper passes and there may be significant shrinkage of the outer diameter in the portion where the paper does not pass. It is known that with this film, wrinkles are liable to occur in a large-sized paper such as letter size or a4 paper when the paper passes through.

An object of the present embodiment is to provide a fixing belt capable of suppressing occurrence of wrinkles in paper even if the belt is formed of a thermoplastic resin.

The fixing belt according to the sixth embodiment has the following manufacturing method and features. PEEK (Victrex381G) was selected as a thermoplastic resin, and extruded from an extrusion molding apparatus. The extruded resin passes through an annular die and is formed into a hollow belt when cooled. In this case, the tape had a longitudinal length of 260mm, an outer diameter of 18.6mm and a film thickness of 100 μm, and was in a substantially uncrystallized state.

Next, a primer was uniformly applied to the outer peripheral surface of the belt, and was coated with a PFA tube (material: DuPont 950HP) having a film thickness of 30 μm. In this case, the tape was introduced into a furnace (DN610H blast thermostat, manufactured by Yamato Scientific co., ltd.) at 220 ℃, calcined for 1 hour, and a PFA tube was bonded to the tape while increasing the crystallinity of the PEEK to substantially the maximum saturation crystallinity. Finally, both longitudinal ends of the hollow-shaped belt were cut so that the longitudinal length was formed to 233 mm.

The maximum saturation crystallinity referred to herein refers to the crystallinity at which the PEEK material has been sufficiently heated above the glass transition temperature of the PEEK material and the change in crystallinity has effectively ceased to occur. Figure 15 shows the crystallinity of the PEEK material with respect to the time of introduction into the furnace at 220 ℃. From fig. 15, it can be confirmed that the crystallinity is substantially saturated when annealing is performed for 1 hour or more. From fig. 2, it can be determined that the maximum saturation crystallinity in this case is 37%.

In this way, the fixing belt according to the present embodiment is molded by extrusion or injection, and preferably, the molded fixing belt is also subjected to an annealing process. In this annealing process, the fixing belt is always calcined at a temperature of 143 to 250 ℃ for 30 to 300 minutes, thereby increasing the crystallinity.

The conditions for measuring the crystallinity in this embodiment are as follows.

The device comprises the following steps: multi-purpose X-ray diffraction system: rigaku Ultima IV

And (3) outputting: 40kV-30mA

Divergent gap: 2/3 degree

Vertical divergence gap limit: 10.00mm

Scattering gaps: 2/3 degree

Light receiving slit: 0.30mm

The measurement conditions were as follows: concentrated beam method

The determination rate is: 5 °/min

Measurement angle range: 2 theta 5-45 deg

By the above-described crystallinity measurement, diffraction peaks were obtained in the amorphous portion and the crystalline portion of the PEEK material, and the crystallinity (%) was calculated from the integrated intensity of the peak at the diffraction angle of 5 to 45 ° from the following formula (2).

Degree of crystallinity (χ c) × 100 (%) … formula (2) (integrated intensity of crystalline portion/integrated intensity of portion including amorphous and crystalline materials (2 θ ═ 5 to 45 °)

The integrated intensity of the crystal portion is the sum of the integrated intensities of peaks appearing in the vicinity of 2 θ of 19 ° (110 plane), 21 ° (113 plane), 23 ° (200 plane), and 29 ° (213 plane).

Through the above procedure, a fixing belt having a longitudinal length of 233mm, an outer diameter of 18.2mm, a film thickness of 130 μm and made of a hollow PEEK material having a crystallinity of 37% was molded. The shape of the fixing belt according to the present invention is not particularly limited, but preferably, the longitudinal length is 216 and 320mm and the outer diameter is 10 to 40 mm. Also, preferably, the PEEK substrate has a film thickness of about 50 to 200 μm. Further, in the case of a two-layer structure covered with a PFA tube, as in the fixing belt of the present invention, the PFA tube is preferably about 10 to 50 μm.

Further, the fixing belt is installed in a fixing device capable of thermally adhering the toner image to the paper.

Comparative example 6 is shown below.

Comparative example 6

In comparative example 6, a fixing belt was manufactured by using PEEK having 20% crystallinity as a base material. The manufacturing method of comparative example 6 is the same as embodiment 6, except for the fact that the calcination time after extrusion is 5 minutes.

In order to confirm the effect of the present embodiment, embodiment 6 and comparative example 6 were compared as shown below.

The postcard paper (100mm wide x 148mm high, 209.5 g/m) is rotated at a speed of 150r/min²) The 50 successive passes are repeated 20 times, and a total of 1000 postcards are passed through the fixing device shown in fig. 2. Then, 100 sheets of Neenah Bond paper (215.9mm wide. times.279.4 mm high, 60 g/m)²) Continuously passed through, and occurrence of wrinkles in the paper was confirmed. Also, the target temperature during the paper passage was set to 150 ℃, and the power input to the heater was controlled accordingly. Fig. 16 shows the surface temperature distribution of the fixing belt during the paper passage in this case. The surface temperature of the fixing belt reaches about 120 ℃ in a portion where the paper passes through and about 200 ℃ in a portion where the paper does not pass through.

Table 5 shows the results of a comparative study of the occurrence of wrinkles in embodiment 6 and comparative example 6. In table 5, when 100 sheets of Neenah Bond paper were passed in series, the case where wrinkling occurred even once was marked as "X" and the case where no wrinkling occurred was marked as "O". In this case, embodiment 6 is "O" and comparative example 6 is "X". In embodiment 6, the effect of suppressing the occurrence of paper wrinkles due to the shrinkage of the outer diameter of the fixing belt was confirmed.

The mechanism behind the suppression of paper wrinkles in embodiment 1 is explained below. Fig. 17 shows the outer diameter distribution in the longitudinal direction of the fixing belt after the comparative study between embodiment 6 and comparative example 6. Accordingly, in embodiment 6, the outer diameter is a stable value of 18.2mm over the entire range in the longitudinal direction. On the other hand, in comparative example 6, the outer diameter was greatly reduced at a position other than the portion where the postcard passed. This is because crystallization of PEEK in the fixing belt is promoted in a portion where the paper does not pass, and thus the difference in outer diameter between the center and the end portion of the fixing belt is increased, causing paper wrinkles. Next, focusing attention on the outer diameter ratio between the center and the end of the fixing belt, the case where paper wrinkling occurs is labeled "X" and the case where no wrinkling occurs is labeled "O". Fig. 18 shows the correspondence between the outer diameter ratio and the occurrence rate of paper cockling.

Accordingly, if the outer diameter ratio exceeds 1.005 (the outer diameter difference between the center and the end of the fixing belt is 0.5%), paper wrinkling occurs. Since there is a difference in moving speed between a portion of the fixing belt that is in contact with the central portion of the paper and a portion thereof that is in contact with the end portion of the paper, a difference in outer diameter is generated. As a result, if a deformation is generated in the paper and the deformation exceeds a prescribed amount, the deformation appears as a paper wrinkle. In this study, a thin paper (60 g/m) which is easily wrinkled even with a small deformation was used²) And (4) passing. That is, using a paper different from the present embodiment, as long as the outer diameter ratio (center/end ratio) between the center and the end of the fixing belt is less than 1.005 (preferably, not more than 1.0045), it is considered that the occurrence of paper wrinkling can be suppressed.

Fig. 19 shows the relationship between the crystallinity of the fixing belt after extrusion molding and the outer diameter ratio (center/end) between the center and the end of the fixing belt in the longitudinal direction after paper passes through. Accordingly, the outer diameter ratio (center/end) of the fixing belt can be suppressed to less than 1.005, provided that the crystallinity is not less than 30%. Further, since the maximum saturation crystallinity of PEEK used in embodiment 6 is 37%, when the state of saturated crystals is set to 100%, the crystallization should proceed to not less than 81%. Therefore, the crystallinity of the crystalline thermoplastic resin used in the fixing belt according to the present embodiment is not less than 81% (preferably, not less than 86%) of the maximum saturation crystallinity of the crystalline thermoplastic resin. Moreover, the crystallinity of the crystalline thermoplastic resin used in the fixing belt of the present embodiment is preferably not less than 30% (more preferably, not less than 32%).

From the results of embodiment 6 and comparative example 6 given above, it can be seen that occurrence of paper cockling can be suppressed by installing a fixing belt in a fixing device in which the crystallinity of the crystalline thermoplastic resin used in the fixing belt is not less than 81% with respect to the maximum saturation crystallinity of the crystalline thermoplastic resin material.

Next, in order to confirm the excellent high-temperature behavior in the present embodiment, an explanation is now given to the difference in bending resistance between the case where a belt material using a thermoplastic resin is installed as a fixing belt in a fixing device and the case where a belt material is installed as an intermediate transfer belt in a transfer device, comparing the results of the study. Therefore, comparative example 7 was prepared and the bending resistance, in other words, the presence or absence of cracking was compared. Comparative example 7 will be described below.

In comparative example 7, a fixing belt was produced in the same manner as in comparative example 6 by using PEEK having a crystallinity of 37% as a base material.

The paper passage conditions in comparative example 7 are shown below. In order to simulate mounting in a transfer device as an intermediate transfer belt, the target temperature was set to 50 ℃ and the power input to the heater was controlled accordingly. The surface temperature of the fixing belt during the passage of the paper in this case reached about 35 ℃. In other words, these conditions do not allow the toner image to be thermally adhered to the paper.

On the other hand, in embodiment 6, on the premise that the toner image can be thermally adhered to the paper, the target temperature of the fixing device is set to 180 ℃ and the power input to the heater is controlled. The surface temperature of the fixing belt during paper passage in this case reaches about 150 ℃, which is a condition that allows the toner image to be thermally adhered to the paper.

In a comparative study, Neenah Bond (215.9mm wide x 279.4mm high, 60 g/m) was rotated at a speed of 150r/min²) The 50 consecutive passes are repeated 20 times, and a total of 1000 sheets are passed through the fixing device shown in fig. 1.

Table 5 shows the results of comparative studies on the occurrence of cracks in embodiment 6 and comparative example 7. When the case where cracking occurred in the fixing belt is denoted as "X" and the case where no cracking occurred is denoted as "O", embodiment 6 is denoted as "O" and comparative example 7 is denoted as "X". From the above, in embodiment 6, it was confirmed that the bending resistance was satisfied and the cracking could be suppressed by installing the fixing belt made of the PEEK material in the fixing device that thermally adheres the toner image to the paper.

Here, regarding embodiment 6 and comparative example 7, the difference in bending resistance is considered. Fig. 7 shows a relationship between the temperature of the fixing belt and the tensile modulus of the fixing belt in this case. Accordingly, the tensile modulus of the fixing belt is greatly reduced from the point where the temperature of the fixing belt exceeds 143 ℃ which is the glass transition temperature (Tg) of the belt material. Furthermore, it is generally known that tensile modulus has a significant correlation with bending resistance.

In embodiment 6, since the rotation operation is performed in a temperature range in which the toner image can be melted, in other words, in a state in which the tensile modulus of the fixing belt is low, the bending resistance is excellent. On the other hand, in comparative example 7, in a temperature range in which the toner image could not be melted, in other words, in a state in which the tensile modulus of the fixing belt was high, the rotation operation was performed, which deteriorated the bending resistance, thus causing cracking. In this way, the fixing belt according to the present invention is preferably used in a temperature range (80 ℃ to 140 ℃) capable of melting a toner image, and particularly preferably used above the glass transition temperature of the crystalline thermoplastic resin of the fixing belt.

Table 5 shows a summary of the results of the comparative studies of embodiment 6, comparative example 6 and comparative example 7.

[ Table 5]

	Paper crumpling	Cracking of
			Embodiment 6	○	○
Comparative example 6	×	○
			Comparative example 7	○	×

In the fixing belt used in the temperature range capable of fusing the toner image, it was confirmed that there is no need to particularly worry about the deterioration of the bending resistance due to the increase in crystallinity as faced in the related art. Therefore, in embodiment 1, the fixing belt having the resin layer formed of the thermoplastic resin which can be produced at low cost is attached to the fixing device, and the occurrence of paper wrinkles due to the shrinkage of the outer diameter of the fixing belt can be suppressed while satisfying the bending resistance.

In embodiment 6, although the fixing belt having the resin layer made of PEEK which is a crystalline thermoplastic resin is used, in the present embodiment, a result similar to that when a resin belonging to the same aromatic ether ketone group is used can also be expected. For example, a tape made of at least one or at least two of the following crystalline thermoplastic resins can be used: polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ether ketone (PEKEKK), polyether ketone (PEKK), polyaryletherketone ketone (PAEEKK), Polyaryletherketone (PAEK), Polyaryletherketone (PAEEK), polyetheretherketone ketone (PEEKK), polyaryletherketone ketone (PAEKK), and Polyaryletherketoneketone (PAEEKK). Of these, PEEK, PEK, or PEKEKK is preferable.

Moreover, even in the case of blending an additive or a crystalline resin or the like with a crystalline thermoplastic resin, similar action and effect can be exhibited. Since the measured value of the crystallinity varies depending on the blending ratio, the action and effect shown in embodiment 6 can be exhibited by determining the maximum saturation crystallinity in the blended material and specifying the crystallinity with respect to the maximum saturation crystallinity in the case of the blended material, and a detailed description thereof will be omitted here, of course. The fixing belt according to the present embodiment has a layer including a crystalline thermoplastic resin, but may have a two-layer structure. For example, a layer including a crystalline thermoplastic resin may be used as the substrate, and a resin such as Perfluoroalkoxyalkane (PFA) may be coated onto the outer peripheral surface of the layer including the crystalline thermoplastic resin. The coating resin may be selected from Perfluoroalkoxyalkane (PFA), Polytetrafluoroethylene (PTFE), and the like.

[ seventh embodiment ]

(description of the apparatus)

Fig. 8 is a cross-sectional view of a fixing device according to a seventh embodiment, and an outline of the fixing device will be described. In the present embodiment, the surface heating fixing device shown in fig. 21 is used. In this configuration, the fixing belt 1 and the pressure roller 3 form a fixing nip portion N, and the surface of the pressure roller 3 is heated by a separate heating roller to supply the heat to the recording material and the toner image T, thereby performing a fixing operation.

A heating roller 12 including a halogen heater 13 as a heating source is pressed against the pressing roller 3, thereby forming a hot-pressing nip H. A fixing nip N is formed by a contact portion between the fixing belt 1 and the pressure roller 3, and when a paper P carrying a toner image T passes through the fixing nip N, the toner image on the paper P can be heated and fixed.

The tape guide 2 is made of a heat-resistant resin, such as liquid crystal polymer, PPS, PEEK, or the like, and its longitudinal end is coupled by a fixing stay (fastening stay)7 supported by the apparatus frame.

A pressing spring (not shown) presses the belt guide 2 toward the pressing roller 3 by applying pressure to the longitudinal end of the fixing stay 7. In this case, the pressing force applied to the pressing roller 3 was 160N and the fixing nip N in this case was 6 mm. In order to fix the stay 7 to transmit the pressing force received by both end portions in the longitudinal direction of the belt guide 2 in a uniform manner, rigidity is increased by adopting a square U-shaped cross-sectional shape using a rigid material such as iron, stainless steel, a pre-coated (Zinkote-based) steel plate, or the like.

Pressing portions (not shown) in both end portions of the heating roller 12 are pressed by pressing springs and pressed against the pressing roller 3. In this case, the pressing force applied to the pressing roller 3 is 160N.

The temperature sensing element 6 contacts the surface of the heating roller 12, and controls the temperature of the fixing device, in other words, the input power of the halogen heater 13, according to the sensed temperature of the temperature sensing element 6.

In the fixing device, the pressure roller 3 and the hot roller 12 are rotated by a driving force from a motor (not shown) that transmits power to the pressure roller 3 and/or the hot roller 12, and the paper P is conveyed by a frictional force acting between the surface of the pressure roller 3, the fixing belt, and the paper P, and the toner is heated and fixed.

The fixing device used in this case is different from the fixing device shown in fig. 2 in that the heating roller as the heating source and the fixing belt do not directly contact each other. In this case, even with such a fixing device, the occurrence of paper wrinkles is suppressed and the occurrence of cracks due to bending resistance can be suppressed.

Embodiment 7 will be explained below. The fixing belt used was a fixing belt manufactured as in embodiment 6, having a longitudinal length of 233mm, an outer diameter of 18.2mm, a film thickness of 130 μm, and made of a hollow PEEK material having a crystallinity of 37% and PFA.

The composition of the pressure roller 3 in embodiment 7 will now be described. The balloonrubber layer was formed to a thickness of 3.4mm on an 11 mm-diameter steel core, and a 150 μm-thick rubber layer having high thermal conductivity was laminated thereon, and further coated with a 10 μm-thick insulating PFA tube, and had a hardness of 56 degrees. The longitudinal length of the elastic layer and the release layer was 229 mm.

In embodiment 7, the presence or absence of paper wrinkles was confirmed under the following conditions. The postcard paper (100mm wide x 148mm high, 209.5 g/m) is rotated at a speed of 150r/min²) The 50 postcards are passed through the post card passage after repeating the 50 postcards for 20 consecutive passes. Then, 100 sheets of Neenah Bond paper (215.9mm wide. times.279.4 mm high, 60 g/m)²) The passage was continued, and the occurrence of wrinkles in the paper was confirmed. Also, the target temperature during paper passage was set to 220 ℃ and the power input to the heater was controlled accordingly. The surface temperature of the fixing belt during the paper passage reaches about 130 ℃ in the portion where the paper passes through and about 200 ℃ in the portion where the paper does not pass through.

When the presence or absence of paper wrinkling in this case was confirmed, it was found that no paper wrinkling occurred. Further, the outer diameter ratio (center/end) between the center and the end of the fixing belt is 1.0005, and therefore can be kept at a value of 1.0045 or less at which the wrinkle suppression effect is obtained.

Next, the presence or absence of a crack due to the passage of paper was confirmed. Regarding the paper passing condition, the target temperature during paper passage in the fixing device was set to 220 ℃ and the power input to the heater was controlled accordingly. After the target temperature is reached, control is performed to start feeding paper to the fixing device. In this case, the temperature of the fixing belt reached 150 ℃. Furthermore, the paper passed through the fixing device at a rotational speed of 150r/min was Neenah Bond paper (215.9mm wide x 279.4mm high, 60g/m²) And 50 sheets of paper were passed through the operation repeatedly 20 times, whereby 1000 sheets in total were passed, as a result, no cracking occurred at all in the fixing belt.

As described above, even in a system in which the heat source and the fixing belt are not in contact with each other, as in the fixing device according to embodiment 7, the fixing belt using a thermoplastic resin that can be manufactured at low cost is attached to the fixing device, and it is possible to satisfy the bending resistance while suppressing the occurrence of paper wrinkles due to the shrinkage of the outer diameter of the fixing belt.

While the present invention has been described with reference to the exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (7)

1. A fixing device for fixing an image on a recording material, comprising:

a heating roller;

a cylindrical film comprising a resin layer made of a crystalline thermoplastic resin; and

a nip forming member that is in contact with an inner surface of the film and forms a nip with the roller via the film,

wherein the image is fixed on the recording material with heat from the roller while the recording material is conveyed by the nip portion,

wherein the crystallinity of the resin layer is not less than 81% of the maximum saturated crystallinity of the crystalline thermoplastic resin.

2. A fixing device according to claim 1, wherein the crystallinity of the resin layer is not less than 86% of the maximum saturation crystallinity of the crystalline thermoplastic resin.

3. A fixing device according to claim 1, wherein the crystallinity of the crystalline thermoplastic resin is not less than 30%.

4. A fixing device according to claim 1, wherein the crystallinity of the crystalline thermoplastic resin is not less than 32%.

5. The fixing device according to claim 1, wherein the crystalline thermoplastic resin is a resin made of any one or at least two of polyetheretherketone, polyetherketone, and polyetherketoneetherketoneketone.

6. The fixing device according to claim 1, wherein the film is set in a state of no tension.

7. A fixing device according to claim 1, wherein the temperature of the film during fixing is above the glass transition temperature of the crystalline thermoplastic resin.

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